Platen turning knob with a paper edge indicator scale

ABSTRACT

A platen turning knob has a transparent cylinder with knurling on a portion of its peripheral surface. An independently rotatable insert member with a paper edge indicating scale provided on its peripheral surface is arranged inside the cylinder. The knob and insert member are slipped onto the end of the roller shaft, and a bar member is snapped onto the end of the shaft to retain the knob and insert member in position.

United States Patent Mankau et al.

[ Apr. 25, 1972 [54] PLATEN TURNING KNOB WITH A PAPER EDGE INDICATORSCALE [72] Inventors: Dieter Mankau; Werner Duddey, both ofWilhelmshaven, Germany [73] Assignee: Olympia Werke AG, Wilhelmshaven,Germany [22] Filed: May 6, 1970 [21] Appl.No.: 35,073

[30] Foreign Application Priority Date May 7, 1969 Germany ..P 19 23239.4

[52] U.S.Cl ..197/189 [51] Int. Cl. ..B41j 29/44 [58] Field of Search..197/187, 189

[56] References Cited UNITED STATES PATENTS 2,633,969 4/1953 Unterweiser..197/189 3,343,643 9/1967 Unterweiser 197/189 3,349,890 10/1967 Russell..19'7/189 1,757,541 5/1930 Murdock. ...l97/l89 2,505,769 5/1950 Hassell..197/189 2,718,956 9/1955 Lepkowski ..197/189 Primary Examiner-Emest T.Wright, Jr. AttorneySpencer & Kaye [5 7] ABSTRACT A platen turning knobhas a transparent cylinder with knurling on a portion of its peripheralsurface. An independently rotatable insert member with a paper edgeindicating scale provided on its peripheral surface is arranged insidethe cylinder. The knob and insert member are slipped onto the end of theroller shaft, and a bar member is snapped onto the end of the shaft toretain the knob and insert member in positron.

4 Claims, 3 Drawing Figures PLATEN TURNING KNOB WITH A PAPER EDGEINDICATOR SCALE BACKGROUND OF THE INVENTION The present inventionrelates to a platen turning knob for typewriters and similar machinesthat has a scale provided thereon for indicating the location of theupper and lower edges of a sheet of paper in the machine.

It has long been known to use an indicator scale to indicate theposition of the upper and lower edges of the sheet of paper in atypewriter.

These indicator scales are known as so-called paper-end indicators. Oneexample of such an indicator is a metal ring bearing the indicator scaleadjustably attached to the platen.

Another known indicator scale is made of an expansible material forattachment to the platen knob for rotation with the platen knob and issettable and adjustable with respect to a fixed marker.

All of these known devices have the disadvantage, however, that theirsetting might unintentionally be changed when the platen knob is beingmanipulated.

In addition, the metal rings attached to the platen itself require anundue amount of space. Their indicator scales are, moreover, not alwaysas clearly visible as desired.

SUMMARY OF THE INVENTION It is, therefore, an object of the presentinvention to provide an indicator device which eliminates thedisadvantages mentioned above, as well as other known drawbacks, andwhich meets practical requirements.

This object is accomplished according to the present invention byproviding a platen knob containing an independently rotatable insertmember having an indicator scale on a portion of its surface.

Among the advantages of the present invention is that the indicatorscale is disposed in a clearly visible and easily readable position and,most of all, that it can not inadvertently be reset when the platen knobis being manipulated.

Further features of the present invention will be apparent from thefollowing description and the drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an exploded view showing theplaten knob of the present invention and a suitable platen shaft formounting the platen knob.

FIG. 2 is a side elevation view, partly in cross section, showing theplaten knob according to the present invention and a suitable platenshaft for mounting the platen knob, together with a portion of atypewriter.

FIG. 3 is an end elevation view of the platen knob according to thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show a knowntypewriter roller, or platen,

shaft 1 which has a collar la and a straight knurled section lb. Platenshaft 1 also has a cylindrical portion 1c, a reduced diameter section 1enear its outer end, and a groove 1d in section 1e. The tip 1f of sectionla is tapered. A platen knob 2 having a housing 2' is mounted on theshaft 1. The housing 2' of the platen knob 2 is constructed, as bymolding of a suitable transparent material, and is shaped like acylinder having an open end and a closed end having a small diameteropening therein, with a smaller diameter co-axial cylinder attached inthe opening at the closed end and in communication with the interior ofthe larger cylinder. Housing 2 is firmly attached to shaft 1 by slidingthe smaller cylinder 2a over the knurled section lbof shaft 1 until itabuts collar la. The inner surface of cylinder 2a is suitably formed todrivingly engage section 1b. The portion 2 b of the outer peripheralsurface of housing 2' that is adjacent its open end is straight knurledto provide a gripping surface to turn the platen, and the remainingportion 20 of the outer peripheral surface of housing 2 is left smooth.

A cylindrical insert member 3 is so dimensioned that it can slide intothe interior of housing 2' and rest on portion 10 of shaft 1 so as to befreely rotatable. The portion of the outer peripheral surface of insertmember 3 adjacent the closed end of housing 2' is provided with anindicator scale 4 which has a circumferentially spaced series ofnumbers. This arrangement of the indicator scale 4 results in its beingdisposed beneath the smooth portion 20 of housing 2. In this manner, thenumbers on the indicator scale 4 can be clearly read through the housing2. Insert member 3 has a recess 3 having rounded corner 3a in the end ofmember 3 adjacent the open end of housing 2'. Recess 3' further has apair of recesses only one of which, 3c, is visible and a diametricallyopposite pair of recesses 3b and 3c in the rounded comer portion 3a.

A U-shaped bar 5 is constructed of a suitable resilient material and isdimensioned to fit into the recess which is not shown and the recesses30 and 3b, 3c with its respective end portions 5c and 5d. Bar 5 also hasresilient portions 50 and 5b, which are shaped to fit over end portionIf and snap into groove 1d of shaft 1 (see FIGS. 1 and 3). This permitsbar 5 to serve as a spring clip for permanently retaining insert member3 in housing 2'.

When the platen turning knob described above is used, for example, on atypewriter 6, a sheet of paper is inserted in the known manner betweenthe platen and the paper guide rollers only to such an extent that thepaper comes into contact with the paper guide rollers of the typewriteror similar machine. Subsequent rotation of the platen pulls the paperbetween the platen and the paper guide rollers until it becomes visiblein front of the platen.

Once the edge of the sheet of paper is visible in front of the platen,the indicator scale 4 on the insert member 3 is indexed. by means of thebar 5, with a marker 7 disposed. for example. on the carriage frame ofthe machine.

The appropriate identifying number for the particular size of paperbeing used is determined in a known manner from a table provided forthis purpose and is the number on the in dicator scale 4 set oppositethe marker 7.

Thereafter, the member 3 will rotate with knob 2 as long as bar 5 is notdisturbed. The recessed position of bar 5 substantially eliminates thedanger of any accidental bar movement.

When using large sheets of paper and small diameter platens; it ispossible that the identifying number determined from the table will comeinto line with the marker 7 several times as the sheet of paper movesthrough the machine. This is immaterial, however, since the approximateposition of the portion of the paper already typed will indicate whetherthe paper is in the end position or in an intermediate position.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes andadaptations, and the same are intended to be comprehended within themeaning and range of equivalents of the appended claims.

We claim:

1. A platen turning knob comprising: an independently rotatable insertmember with a scale thereon for indicating the upper and lower edges ofa sheet of paper; a housing member of a transparent material and havinga portion of its outer peripheral surface knurled for gripping; saidinsert member having two ends with one end provided with a recess havingrounded sides; and a bar member which fits into said recess; saidhousing member being attached to a platen shaft for rotation with theplaten shaft, said insert member being rotatably mounted on the platenshaft and said bar member being constructed in a U-shaped of resilientmaterial, and including two legs with a portion of each leg formed toengage a groove on the platen shaft, said bar member serving forrotating said insert member.

2. A platen knob as defined in claim 1, wherein said insert member hastwo diametrically opposite pairs of recesses in the rounded comer of therecess defined in the end of said insert member, each one of each pairof recesses accepting and retaining a portion of said bar member.

3. A platen knob as defined in claim 2, wherein said scale is arrangedon said insert member to be clearly visible through said transparenthousing.

4. A platen knob as defined in claim 3, wherein said housing member is ahollow cylinder open at one end and substantially 5 closed at the otherend, and said insert member is a cylinder which fits within the hollowinterior defined by said housing member.

1. A platen turning knob comprising: an independently rotatable insertmember with a scale thereon for indicating the upper and lower edges ofa sheet of paper; a housing member of a transparent material and havinga portion of its outer peripheral surface knurled for gripping; saidinsert member having two ends with one end provided with a recess havingrounded sides; and a bar member which fits into said recess; saidhousing member being attached to a platen shaft for rotation with theplaten shaft, said insert member being rotatably mounted on the platenshaft and said bar member being constructed in a U-shaped of resilientmaterial, and including two legs with a portion of each leg formed toengage a groove on the platen shaft, said bar member serving forrotating said insert member.
 2. A platen knob as defined in claim 1,wherein said insert member has two diametrically opposite pairs ofrecesses in the rounded corner of the recess defined in the end of saidinsert member, each one of each pair of recesses accepting and retaininga portion of said bar member.
 3. A platen knob as defined in claim 2,wherein said scale is arranged on said insert member to be clearlyvisible through said transparent housing.
 4. A platen knob as defined inclaim 3, wherein said housing member is a hollow cylinder open at oneend and substantially closed at the other end, and said insert member isa cylinder which fits within the hollow interior defined by said housingmember.